Fertilizing orchids has always been a mystery for the novice orchid grower, but once you understand your orchids it is very easy, as I’ll show you below.
It’s no surprise that fertilizing orchids is confusing since manufacturers go out of their way to make it complex. First of all, they sell special containers labeled for orchids. Here is your first news flash – there is no such thing as orchid fertilizer, and I will prove it below.
Secondly, they sell products you don’t need, like this orchid plant food mist. Not only is misting not good for orchids, but they don’t need a foliar fertilizer. If you think that misting helps keep the humidity high, have a look at Increasing Humidity for Indoor Plants – What works and What Doesn’t. But even that does not bother me too much. What really ticks me off is the price they charge for these products – its criminal.
What is Orchid Fertilizer?
There is no such thing. Orchids use the same nutrients as all other plants – there are no mystery ingredients in orchid fertilizer.
Let’s have a look at the ingredients in Miracle-Gro Orchid Plant Food Mist. It contains the following.
- Urea
- Ammonium phosphate
- Potassium phosphate
- Potassium nitrate
The last three are found in almost every fertilizer. Urea is very common in lawn fertilizer and products that need a cheaper source of nitrogen.
Miracle-Gro Orchid Plant Food Mist
Before I go any further, I want to make it clear that there is nothing wrong with this fertilizer. It is a good product, and I use Miracle-Gro on my orchids – I just don’t use this product.
This product is a very dilute fertilizer with an NPK of 0.2-0.2-0.2. That is 0.2% nitrogen and nitrogen is the nutrient that plants need most, so it is also the nutrient you are paying for.
The bottle contains 236 ml. Of that 99.4% is water. The cost on Amazon is about $10 US. It is a bit cheaper if you buy multi-packs
Make Your Own Plant Food Mist
Assume you want to apply a foliar mist to your orchids and you are willing to make your own. What would it cost?
Miracle-Gro also sells a soluble tomato fertilizer (18-18-21) with the same NPK ratio, a 1-1-1. This product can be easily dissolved in water and you can make a 0.2-0.2-0.2 mixture.
Concerned about it being a tomato fertilizer? Don’t be – there is no such thing as a tomato fertilizer, except in the minds of marketing people. It has the same ingredients as all other fertilizer.
Cost of the Nitrogen in Miracle-Gro Orchid Plant Food Mist
This product contains 0.2% nitrogen in 236 ml, which is 236 g. Each bottle contains 0.5 g nitrogen, at a cost of $10.
Cost of nitrogen in Tomato Fertilizer
The Miracle-Gro tomato fertilizer also costs $10 for 18% nitrogen, in a 680 g box.
The box of fertilizer contains (680 X 18%) 122 g of nitrogen and costs $10. So 0.5 g of nitrogen costs $0.04.
When you buy Miracle-Gro Orchid Plant Food Mist you are paying $10 for $0.04 of nitrogen.
Make Your Own Fertilizer
Consider this. You could buy the soluble tomato fertilizer mentioned above and make your own spray. For $10, you can buy enough fertilizer to make 244 bottles of plant food mist. This is a savings of $2,430.00, not including shipping.
Does Foliar Feeding Work for Orchids?
Foliar feeding does work for specific situations, certain types of plants and for some of the micronutrients. It is a poor way to feed macronutrients to any plant, and the above plant food mist only supplies macronutrients. It is not a good choice for foliar feeding. You can find more about this topic in Foliar Feeding – Does It Work?
Orchids are special plants. Their leaves have a very thick waxy coating designed to keep moisture in. If moisture does not travel easily through the leaves, it becomes clear that a foliar feed won’t either. Orchids have few stomata, but contrary to what many believe, stomata are not the entry point for nutrients in a foliar spray. This takes place through micro-pores and it is unclear to me if orchids have these.
Foliar feed is not a good way to fertilize orchids. Apply fertilizer to the roots.
A Better Way to Fertilize Orchids
I like growing orchids on a solid media, like coco chunks, where they grow very well and are easy to water and fertilize. I fertilize while I water as shown in this video and I use whatever soluble fertilizer is on sale, provided it contains micronutrients.
If you prefer water culture, just add a small pinch of any soluble fertilizer into the water when you change it.
Orchid Care
For complete orchid care, watch this set of 8 YouTube videos: https://www.youtube.com/watch?v=sfo8JIjtkH0&list=PLq7hmpP9i05QQcIDQQb9RnNa4s62CrWms
Note that the links to fertilizer on this page are affiliate links. If you use them to go to Amazon, and buy any product, Garden Myths will get a small commission, which offsets the cost of this free site. It costs you nothing extra.
Thanks. This is great info! I’m happy to know I have been watering my orchids correctly. I had my first blooms this year and have more confidence. After reading your article about this, I’m wondering if I should just use this product as is to water my orchids. Should I dilute it or not? I don’t want to use it as directed, but don’t want to waste it.
Just add some to your water when you water.
I want to use the tomato miracle grow as a spray for my Hoyas. The orchid foliage spray seems to really help them. Can you tell me how to dilute it down to the .02-.02.02 that you were talking about? How many tsp per gallon.
Thank you
Robert made a minor error that resulted in a 10-fold discrepancy in his calculations.
Correction: Orchid mist is 0.02-0.02-0.02 of pre-diluted fertilizer; not 0.2-0.2-0.2.
1 ml of water weighs 1 g.
Since Orchid mist is 99.4% water, we can assume that the weight of 1 ml of Orchid mist weighs 1 g.
The amount of N in 236 ml of Orchid mist is 0.0472 g which works out to 0.2000 g/L of N.
To make 1 L of Orchid mist using 18-18-21 water soluble Tomato fertilizer you would need:
0.2000 / 0.18 = 1.11 g of Tomato fertilizer
1.11g of 18-18-21 Tomato fertilizer would give a concentration of 200 PPM of N which is a standard concentration Miracle-Gro uses for indoor plants.
If interested in calculating PPM you can find the formula here: https://ag.umass.edu/greenhouse-floriculture/fact-sheets/fertilizer-calculations-for-greenhouse-crops
This means that a single 680g box of water-soluble Tomato fertilizer will make 2593 bottles of Orchid mist.
Miracle-Gro has changed their packaging, and now Tomato fertilizer comes in a 500g box, a better value is Miracle-Gro Water Soluble Plant Food 20-20-20 at $8.98 CDN for a 680 g box at Walmart.
Using this product, you use 1g of 20-20-20 fertilizer to create a solution with a concentration of 200 PPM of N.
This works out to 680 L of solution, or 680 / .236 = 2881 bottles of Orchid Mist for $8.98 at $0.003 per bottle.
Conclusion: Only buy this product if money has no value to you. Make your own.
Thanks for the correction. I have updated the post.
By accident I came across your website today. Thank Heavens!
I was about to blow a big wad of cash on the wrong soil and fertilizers. Thank You! And thanks for the much needed info on orchids.
Roland, it’s not slander to explain the ratio of water to compounds in the Miracle Gro products. Furthermore, the site recommends the MG tomato fertilizer as a good candidate to dilute for orchids. Looks fair to me.
Hello, I am using a slow-release fertilizer (triple 16 or 17, sorry, I can’t remember). I leave a few of these small granules overnight in water, the night before I am watering the orchid. I just bought the orchid a few month ago and so far so good, but I wonder if do you see any problems with using slow-release fertilizer that may show up in the long run.
I have another less related question: I am leaving for a month and a half and was planning to put my orchid in a plastic bag, near a window with a shadow and a wet piece of cotton inside the bag. I read this creates a green house that would keep the plant alive for months, would you agree with that?
Thanks a lot for your comments!
slow release fertilizer will not leach out many nutrients with an overnight soak. Use a soluble fertilizer instead.
Don’t put the orchid in a bag – it will likely get fungus or bacterial rot. A month and a half without water will not kill an orchid. Just leave it.
http://www.gardenmyths.com/orchids-need-water/
Thanks a lot, that’s very helpful!
Why the Miracle-Gro tomato fertilizer and not the regular all purpose Miracle-Gro fertilizer? thank you
I picked it because it has the same NPK – a different NPK would also work.
Thanks for the information, I do have a question, 2 years ago I bought a phalaenopsis orchid, since then it has never stopped blooming, I water it once a week, don’t let it stay wet, it has never been fertilized, it is in a south west facing window
What have I done right? I’m asking because I have had other phalaenopsis that have only bloomed sporadically and died within 12 months.
I would suspect they had different media. Also, different types of phals will bloom for different lengths of time. Sone of the smaller flowered ones bloom continuously – larger flowered ones tend to take a rest.
I would give it some fertilizer.
The flood water method probably simulates the manner orchids are watered and fertilized in nature, with a sudden heavy flood of water full of dissolved nitrates. Tap water has no nitrogen hence the amendment is needed.
Phals grow in trees – I doubt many get flooded.
I think I know what Kelley means. I’ve seen them growing in PNG and Indonesia on the side of cliffs where they are subject to torrential tropical downpours and water running down the rock faces for hours on end.
Thanks Robert
I kind of like this. You slander off Miracle Pro, but still try to make money of them by linking to their Amazon listed products.
But I totally agreee with you, all these special fertilizers are a big rip off. My pet is bamboo fertilizer, which is the same as lawn fertilizer at three times the price.
But then again many people are suckers and feel good about using the “right” product. They want to get fooled.